WEDNESDAY, Jan. 6 (HealthDay News) -- A coalition of clean air advocacy groups wants the U.S. Environmental Protection Agency (EPA) to propose new standards that would reduce allowable levels of smog-causing ozone.

Current standards, which have reduced smog by about 5% a year, are still too weak, with some 186 million Americans breathing unhealthy air, according to the American Lung Association.

"The upcoming EPA plans to review national clean air standards for ground level ozone may be the single most important environmental decision the EPA makes this year," Frank O'Donnell, president of Clean Air Watch, said during a teleconference Wednesday.

"It will literally determine the quality of air we breathe in America for the next decade and probably beyond," he added.

In 2008, the EPA completed a smog review and recommended tough new standards, but the Bush administration rejected the advice of its science advisors and adopted a weaker version, O'Donnell said.

It took a lawsuit from health and environmental groups for the EPA to take a new look at the ozone standards, he said.

The EPA was repeatedly told by scientists, environmental groups and health advocates that the standard must be between 60 and 70 parts per billion in ambient air, said Janice Nolen, national policy director of the American Lung Association.

"Somehow EPA decided that all that expertise was wrong. EPA announced a standard of 75 parts per billion," she said.

Critics of tighter standards cite the recession, increased costs to industry and lack of technology as reasons not to enact them, Nolen noted. They maintain "the air is clean enough," she said.

"I promise you we hear these same arguments every time the EPA reviews the standards," she added. "Nearly 40 years of evidence shows that these arguments are not true."

Children, the elderly and people with chronic lung disease are paying the cost of air pollution, Nolen said.

Ozone actually burns the airways and lungs, causing inflammation, said Dr. Norman H. Edelman, chief medical officer of the American Lung Association, during the teleconference.

In healthy people, this inflammation can cause difficulty breathing, coughing, wheezing and chest pain, he said.

For people predisposed to respiratory problems, such as asthma or chronic obstructive pulmonary disease, the consequences are more serious. "They are at great risk because they can't handle the burden of additional inflammation in their already inflamed lungs," Edelman said.

For these people, smog causes more attacks and more hospital visits and can even shorten their lives, he added.

Anyone with heart disease is also at increased risk of dying from breathing ozone, he said. Even some otherwise healthy people can't handle high ozone levels, Edelman added.

David Baron, an attorney with Earthjustice and another speaker at the teleconference, said he hopes the EPA will set stricter ozone standards for ecosystems and wildlife.

These so-called secondary standards could be even more stringent than those set for human health, Baron said.

"We hope the EPA will adopt a strong second standard to protect our forests from ozone damage, around 7 parts per million," he said.

If the EPA does propose a new standard, public hearings will follow. The recommendations would not be final until August, Nolen said.

It would then take a decade or more before the full impact would be seen in improved air quality, she said.